Blended learning, which combines independent online work with in-person group sessions, can support educator development while promising time-savings, flexibility, learner autonomy, and ease of use -- all without sacrificing program quality. Indeed, two decades of peer-reviewed studies of in-person, online, and blended instruction have consistently demonstrated that quality trumps delivery method. To more deeply understand the opportunities and challenges of blended learning, New Leaders examined a series of innovative, blended programs designed specifically for public school leaders and faculty. These programs incorporated independent online instructional components with in-person professional development sessions, job-embedded practice, and personalized coaching. Made possible by a grant from the Bill and Melinda Gates Foundation, the Blended study examined programs implemented by New Leaders during school year 2017-18 with more than ten partners, including urban and rural districts and charter schools. [For the executive summary, see ED605812.]